THI: 1 1: i : DING VALUE OF CEREALS AS CALCULATED 



FROM CHEMICAL ANALYSES. 



INTRODUCTION. 



The chemical jmdy>i- of grains and other materials used in feeding 

 domestic animal- consists in the determination of the nutritive sub- 

 stances contained therein. The results of such determinations are 

 expressed in percent age amounts, usually, as pounds per 100 pounds. 

 From these determinations the value of the food for feeding purposes 



>tained. 



The e--ential nutritive materials contained in all foods are com- 

 pri-ed within the three elates of substances, proteins, fats, and 

 hydrate-, and the determination of these is the object of a 

 feeding ti ill' analy>i> when its food value is desired. In order that 

 the re-nit- of N.-iriou-s ;mal\>es may be directly comparable the 

 nioi-iure < ontnit of the food is found, and from this the amounts of 

 the t her constituent - are calculated to a uniform water-free, or dry, 

 la>i-. Another determinat ion is also made, namely, that of the ash 

 or mineral The mineral >uhstances present in a food play 



an important part in the pli ;il pnu ess of digestion, but pos- 



sess no \-:di;- >iirce of energy. Their action is mainly 



indirect, an.: Method of measuring their value is known, they 



n..t considered in calculating the nutritive value of foods. The 

 therefore, of \pre-Miii: the results of an analysis of a 

 b food i th<> amounts of the following substances present: 



protein, fat. and carbohydrate; the food value of the 

 material bein-_r l.a-e.l on the la>t three. 



In the study of Mich complex materials as feeding stuffs, however, 

 it has I. eeii found that a knowledge of the total amounts of these 

 three nutritive constituent- i- not sufficient to give an exact idea of 

 the pood value of any Mib>t;meo. This is due to factors depending, 

 HIM. on the < haracter of the food itself and, second, on that of the 

 animal UMII-J- it. The three groups f substances proteins, fats, and 

 tea .! not yield all of their material to the animal as 

 nutriment, nor are they nutritive in equal degrees. The proportion 

 that i- actually digested and used by the animal is different in each 

 ach possesses a certain coefficient of digestibility. Fur- 

 thermore. eah of these groups as ordinarily determined contains 

 separate and distinctly different substances which, under certain 

 conditions or when present in small amounts, may be disregarded, 

 but which, when present in large amounts or when productive of 

 decided HlV-t>. even though in small quantities, must be considered 

 irately. 



